Method getMaxMatrix

java/Chapter 18/Question18_12/QuestionB.java:6–26

(int[][] original)

public class QuestionB {
	public static int getMaxMatrix(int[][] original) {
		int maxArea = Integer.MIN_VALUE; // Important! Max could be < 0
		int rowCount = original.length;
		int columnCount = original[0].length;
		int[][] matrix = precomputeMatrix(original);
		for (int row1 = 0; row1 < rowCount; row1++) {
			for (int row2 = row1; row2 < rowCount; row2++) {
				for (int col1 = 0; col1 < columnCount; col1++) {
					for (int col2 = col1; col2 < columnCount; col2++) {
						int sum = computeSum(matrix, row1, row2, col1, col2);
						if (sum > maxArea) {
							System.out.println("New Max of " + sum + ": (rows " + row1 + " to " + row2 + ") and (columns " + col1 + " to " + col2 + ")");
							maxArea = sum;
						}
						
					}
				}
			}
		}
		return maxArea;
	}
		
	private static int[][] precomputeMatrix(int[][] matrix) {
		int[][] sumMatrix = new int[matrix.length][matrix[0].length];